1. Field of the Invention
Embodiments of the present invention are directed to the decontamination of industrial fluids and, in particular, to the decontamination of cooling fluids utilized in tire manufacturing processes.
2. Description of the Related Art
The manufacturing of tires involves multiple steps, which typically include: mixing the rubber components, calendaring, extrusion, assembly, vulcanizing, inspection, and repair if needed. Certain steps in the tire manufacturing process involve the use of fluids to cool heated rubber compositions. For example, direct contact cooling systems are typically used to control the rate of tire tread and tire line cooling. These cooling systems are an important part of the tire manufacturing process.
The liquid vehicle for these cooling fluids is often water, including demineralized or deionized Water (DI). Unfortunately, cooling fluids utilized in tire-manufacturing process, especially water-based fluids, are susceptible to bacteria, algae, fungi, yeasts, molds and other microbial propagation. Biological contamination is usually associated with the formation of biofilm. As discussed in more detail below, biological contamination of these fluids can be costly and dangerous, thus, some biological control for these fluids is desired.
To confront this problem, the tire manufacturing industry has typically relied on the use of biocides such as iso-thiazoline and glutaraldehyde to control the levels of bacteria and algae in direct contact cooling water systems. However, using biocides can create additional problems.
For example, handling biocides can be dangerous for the workers. In addition, it is difficult to manually or automatically dose the biocide to the cooling system because the water to be treated is a relatively small volume. Furthermore, biocide is typically administered intermittently, from about once per week to up to several times per week. Thus, the dosage is not always applied on a consistent and predictable basis.
Additionally, the overuse of biocide chemicals is undesirable as it may affect the water chemistry, including the pH. The change in water chemistry could in turn affect the quality of the manufactured tires and/or manufacturing equipment. For example, when oxidizing biocide agents such as chlorine or bromine are used, overfeed of these compounds is corrosive to the manufacturing system metallurgy.
While chemical methods may be able to control the circulating water bacteria to some extent, ultimately, the microorganisms overcome the biocides and the microbial degradation of the fluid and contaminants results in foul odors in the work environment. Furthermore, even with microbial control, the use of biocides still results in significant accumulations and masses of biological deposits that typically develop throughout the system. Accordingly, the system usually has to be manually cleaned at least once per year and usually at least twice per year. This typically involves vacuuming out the accumulated sludge from the sumps and properly disposing it.
In addition to microbial propagation, the cooling fluids used in tire manufacturing also tend to accumulate silt, sediment, and other material (e.g., rubber) that regularly collect in the sump. While biocides can be used to treat microbial propagation, they are not effective at reducing additional materials, such as rubber, that accumulate in cooling fluids.
To obtain long usage of tire-manufacturing cooling fluid, it is desirable to develop a treatment of the fluid that does not modify its desired composition or characteristics. This is especially true when the changes in the cooling fluid negatively affect the quality of the manufacturing equipment or finished tire. Accordingly, there is a need in the art for an effective and new method of treating cooling fluids utilized in tire-manufacturing processes without the use of large amounts of biocides, and which can provide uniform protection, or substantially uniform protection with time.